As is well known the variable vane/stator of a gas turbine engine serves to change the geometry of the engine and typically, serves to change the direction of the engine's working medium flowing from one compressor or turbine stage to the next.
The stator/vane assembly generally includes a mount rotatable about a radially oriented axis for each individual stator vane which is in turn, connected to a synchronizing (sync) ring. Such assemblies may use a plurality of lever arms to connect each individual mount to the sync ring so that movement of the sync ring will cause uniform movement to each individual vane/stator.
Actuation of the lever arm by the sinc ring results in out of plane rotation of the lever arm. This motion has been accommodated by several methods in prior designs, such as uniballs, sloppy pin and bushing and flexible arms. The flexible arm approach is considered superior from a joint wear and vane accuracy standpoint. However, the disadvantage of the flexible arm concept is eventual fatigue of the arm.